package com.asiainfo.security;

import java.util.Collection;
import java.util.Iterator;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.security.access.AccessDecisionManager;
import org.springframework.security.access.AccessDeniedException;
import org.springframework.security.access.ConfigAttribute;
import org.springframework.security.authentication.InsufficientAuthenticationException;
import org.springframework.security.core.Authentication;
import org.springframework.security.core.GrantedAuthority;

/**
 * 用户是否拥有所请求资源的权限
 * @author luhf
 * @date 2013-1-20 下午1:52:54
 */
public class MyAccessDecisionManager implements AccessDecisionManager{
	
	private static final Logger log=LoggerFactory.getLogger(MyAccessDecisionManager.class);

	@Override
	public void decide(Authentication authentication,Object arg1,Collection<ConfigAttribute> configAttributes) throws AccessDeniedException, InsufficientAuthenticationException{
		if(configAttributes==null){
			return;
		}
		// 所请求的资源拥有的权限(一个资源对多个权限)
		Iterator<ConfigAttribute> iterator=configAttributes.iterator();
		while(iterator.hasNext()){
			ConfigAttribute configAttribute=iterator.next();
			// 访问所请求资源所需要的权限
			String needPermission=configAttribute.getAttribute();
			log.debug("needPermission is {} "+needPermission);
			// 用户所拥有的权限authentication
			for(GrantedAuthority ga:authentication.getAuthorities()){
				if(needPermission.equals(ga.getAuthority())){
					return;
				}
			}
		}
		// 没有权限
		throw new AccessDeniedException("没有权限访问!");

	}

	@Override
	public boolean supports(ConfigAttribute arg0){
		return true;
	}

	@Override
	public boolean supports(Class<?> arg0){
		return true;
	}

}
